The present invention relates to pyruvic acid and, in particular, to an improved method for the production of pyruvic acid.
Pyruvic acid is used as a flavor enhancer and as an intermediate compound in biochemical reactions. Heretofore, pyruvic acid has been generally prepared in commercial quantities by the thermal decomposition of tartaric acid in the presence of a suitable dehydration agent.
The tartaric acid was obtained from the reaction of sulfuric acid with an aqueous solution of potassium bitartrate, which is a natural product. The most widely used dehydration agents were potassium bisulfate and potassium pyrosulfate. The reaction was as follows: EQU C.sub.4 O.sub.6 H.sub.6 + KHSO.sub.4 .fwdarw.C.sub.3 O.sub.3 H.sub.4 + CO.sub.2 + H.sub.2 O + KHSO.sub.4
unfortunately, the yield of pyruvic acid product from the reaction is relatively low, i.e., approximately 60%, which results in a relatively expensive pyruvic acid product. The unfavorable economic effect of the low yield is compounded by the fact that tartaric acid itself is a relatively expensive starting material. Therefore, the art has long sought a straightforward and inexpensive method for producing pyruvic acid. This search has resulted in the development of other methods for the production of pyruvic acid. For example, it was found that pyruvic acid can be prepared by the hydrolysis of acetyl cyanide or oxalacetic ester or by the distillation of glyceric acid in the presence of a dehydrating agent. However, these methods have proved to be of only academic interest and are not adaptable to commercial use due to the high cost of the starting materials and the low reaction yields.